The present disclosure relates to sonar equipment. More particularly, it relates to depth displaying accessories for use with a flasher type sonar system.
Sonar systems have long been used by anglers to gauge the depth of the body of water being fished, as well as the presence and depth of fish (commonly referred to as a “depth finder” or a “fish finder”). Sonar systems use a transducer (e.g., electroacoustic transducer) to generate a sonar pulse that is directed down through the water. The transducer receives a sonar echo return from the bottom of the body of water, as well as sonar returns from fish or other objects in the water and located within the transducer's sonar cone. The depth (or distance) and size of solid objects (e.g., fish, lure, bottom of the body of water, etc.) are then estimated based upon the speed and intensity of the echo return waves relative to the original sonar pulse. The estimated information is then signaled to a display.
With flasher type fish or depth finders, the display (or display unit) typically includes a housing having a circular ring lens or window with an adjacent scale indicative of a distance below the transducer. Mounted within the housing is a motor that turns a disc on which one or more light sources are maintained. As the disc rotates, light is emitted by the light sources at different positions around the ring to represent sonar returns from objects, as well as from the bottom of the body of water. The rotational position of the emitted light relative to a top dead center of the circular scale generally indicates a scaled distance or depth of the objects relative to the transducer.
With some flasher type fish finders, the transducer is permanently attached to or carried by the display unit's housing. Alternatively, the transducer can be part of a transducer assembly having a cable that is selectively connected to the display unit's housing (with the display unit further including various circuitry and controllers for operating the flasher type system). Such systems are widely used, for example, with ice fishing. During use, the transducer assembly is plugged into a port of the primary display unit. Additionally, at least one selector knob or other user input actuator is included with the primary display unit (e.g., assembled to the housing near the display) that allows the user to select a desired depth range (typically in ten foot increments). When the flasher type fish finder system is used by an angler on a body of water at a location having an unknown depth, the user makes a best guess as to the depth of the area being fished and “enters” this guess at the range selector knob. During operation, the flasher display gives a general indication as to the body of water's sensed “bottom,” but does not provide any numerical depth information. Anglers often wish to know the actual depth. Moreover, if the actual depth is well outside of the selected range, the user will be generally apprised by the flasher display that a different depth range should be selected, but will not know what a more appropriate range setting might be.
In light of the above, a need exists for a device useful with conventional flasher type fish finder units and capable of providing a user with more exacting depth information.